ggplot2 and color model

colormodel.R

library(ggplot2)

# http://www.cookbook-r.com/Graphs/Colors_(ggplot2)/
# The palette with grey:
cbPalette <- c("#999999", "#E69F00", "#56B4E9", "#009E73",
               "#F0E442", "#0072B2", "#D55E00", "#CC79A7")

data(iris)
p <- ggplot(iris) +
  geom_histogram(aes(Sepal.Length, fill = Species),
                 binwidth = 0.5) +
  scale_fill_manual(values = cbPalette)

ggsave("ggsave.pdf", plot = p, device = "pdf",
       width = 12, height = 8, units = "cm")

pdf("ggplot-grey.pdf", width = 12 / 2.54, height = 8 / 2.54,
    colormodel = "grey")
print(p)
dev.off()

pdf("ggplot-cmyk.pdf", width = 12 / 2.54, height = 8 / 2.54,
    colormodel = "cmyk")
print(p)
dev.off()

ggplot-cmyk.pdf

ggplot-grey.pdf

ggsave.pdf